From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <yskoh@mellanox.com>
Received: from mellanox.co.il (mail-il-dmz.mellanox.com [193.47.165.129])
 by dpdk.org (Postfix) with ESMTP id 518CB1B8FD
 for <dev@dpdk.org>; Thu, 10 Jan 2019 19:35:38 +0100 (CET)
Received: from Internal Mail-Server by MTLPINE1 (envelope-from
 yskoh@mellanox.com)
 with ESMTPS (AES256-SHA encrypted); 10 Jan 2019 20:35:33 +0200
Received: from scfae-sc-2.mti.labs.mlnx (scfae-sc-2.mti.labs.mlnx
 [10.101.0.96])
 by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id x0AIZU9D030124;
 Thu, 10 Jan 2019 20:35:31 +0200
From: Yongseok Koh <yskoh@mellanox.com>
To: olivier.matz@6wind.com, shahafs@mellanox.com
Cc: dev@dpdk.org, roszenrami@gmail.com, david.marchand@redhat.com
Date: Thu, 10 Jan 2019 10:35:27 -0800
Message-Id: <20190110183528.42503-1-yskoh@mellanox.com>
X-Mailer: git-send-email 2.11.0
In-Reply-To: <20190109085426.39965-1-yskoh@mellanox.com>
References: <20190109085426.39965-1-yskoh@mellanox.com>
Subject: [dpdk-dev] [PATCH v3 1/2] mbuf: add function returning default
	buffer address
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Thu, 10 Jan 2019 18:35:38 -0000

This patch introduces two new functions - rte_mbuf_buf_addr() and
rte_mbuf_data_addr_default().

rte_mbuf_buf_addr() reutrns the default buffer address of given mbuf which
comes after mbuf structure and private data.

rte_mbuf_data_addr_default() returns the default address of mbuf data
taking the headroom into account.

Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
---

v3:
* rename functions

v2:
* initial implementation

 lib/librte_mbuf/rte_mbuf.h | 43 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index bc562dc8a9..486566fc28 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -788,8 +788,47 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi)
 }
 
 /**
+ * Return the default buffer address of the mbuf.
+ *
+ * @param mb
+ *   The pointer to the mbuf.
+ * @param mp
+ *   The pointer to the mempool of the mbuf.
+ * @return
+ *   The pointer of the mbuf buffer.
+ */
+static inline char * __rte_experimental
+rte_mbuf_buf_addr(struct rte_mbuf *mb, struct rte_mempool *mp)
+{
+	char *buffer_addr;
+
+	buffer_addr = (char *)mb + sizeof(*mb) + rte_pktmbuf_priv_size(mp);
+	return buffer_addr;
+}
+
+
+/**
+ * Return the default address of the beginning of the mbuf data.
+ *
+ * @param mb
+ *   The pointer to the mbuf.
+ * @return
+ *   The pointer of the beginning of the mbuf data.
+ */
+static inline char * __rte_experimental
+rte_mbuf_data_addr_default(struct rte_mbuf *mb)
+{
+	return rte_mbuf_buf_addr(mb, mb->pool) + RTE_PKTMBUF_HEADROOM;
+}
+
+/**
  * Return the buffer address embedded in the given mbuf.
  *
+ * Note that accessing mempool pointer of a mbuf is expensive because the
+ * pointer is stored in the 2nd cache line of mbuf. If mempool is known, it
+ * is better not to reference the mempool pointer in mbuf but calling
+ * rte_mbuf_buf_addr() would be more efficient.
+ *
  * @param md
  *   The pointer to the mbuf.
  * @return
@@ -798,9 +837,7 @@ rte_mbuf_from_indirect(struct rte_mbuf *mi)
 static inline char *
 rte_mbuf_to_baddr(struct rte_mbuf *md)
 {
-	char *buffer_addr;
-	buffer_addr = (char *)md + sizeof(*md) + rte_pktmbuf_priv_size(md->pool);
-	return buffer_addr;
+	return rte_mbuf_buf_addr(md, md->pool);
 }
 
 /**
-- 
2.11.0